Influence of the physical-chemical properties of polyaniline thin films on the final sensitivity of varied field effect sensors

Author(s)

Pedroza Dias Mello, Hugo Jose Nogueira ^[1] ; Heimfarth, Tobias ^[1] ; Mulato, Marcelo ^[1]

Affiliation

^[1] Univ Sao Paulo, Dept Phys, Fac Philosophy Sci & Letters Ribeirao Preto, BR-14040901 Ribeirao Preto, SP - Brazil

• Document type: Journal article
• Source: Materials Chemistry and Physics; v. 160, p. 257-263, JUN 15 2015.
• Web of Science Citations: 9

Abstract

We investigated the use of electrodeposited polyaniline (PANI) thin sensing films in pH sensors. Two configurations of the Extended Gate Field Effect Transistor (EGFET) sensor were studied: the Single EGFET (S-EGFET) and the Instrumental Amplifier EGFET (IA-EGFET) setups. The films were analyzed in both systems and the sensitivity and linearity of each sensor were compared. Initial sensitivities (70-80 mV/pH) measured in the IA-EGFET were reduced due to polymer bulk protonation after a prior measurement in the S-EGFET system. Films with high amount of deposited polymer had their sensitivities least reduced. Bulk protonation occurred due to the step potential applied to the reference electrode in the S-EGFET system. These changes were also analyzed by scanning electron microscopy (SEM), visible reflectance spectroscopy and evaluation of CIE L{*}a{*}b{*} color scale. PANI pH EGFET sensors exhibited good linearity and stability that along with their high sensitivity, easy processing and low cost film production have large potential applications. (C) 2015 Elsevier B.V. All rights reserved. (AU)

• FAPESP's process: 14/09562-4 - Microelectronic biossensors associated with electrochemical techniques
• Grantee: Marcelo Mulato
• Support Opportunities: Regular Research Grants
• FAPESP's process: 09/09163-4 - Development of planar fluxgate magnetic microsensors
• Grantee: Marcelo Mulato
• Support Opportunities: Regular Research Grants